K+ channels are structurally and functionally diverse families of K+-selective channel proteins which are ubiquitous in cells, indicating their central importance in regulating a number of key cell functions. K+ channels are important regulators of numerous biological processes, including secretory processes, muscle contraction, and post-ischemia cardioprotection. Electrophysiological studies have disclosed the existence of K+ channels in nearly all cell types.
Spreading depression is an abrupt rise in extracellular potassium ([K+]o) and depression of electrical activity in nervous tissue; it shares many characteristics of cortical spreading depression (CSD) (Leão, A. A. P., J. Neurophysiol. 7:359-390, 1944). In mammalian tissue, CSD has been associated with several important pathologies including stroke, seizures and migraine (Smith et al., Biol. Rev. Camb. Philos. Soc. 81:457-481, 2006; Somjen, G. G., Neuroscientist 8:254-267, 2002; Somjen, G. G., Physiol. Rev. 81:1065-1096, 2001). CSD is increasingly accepted as a primary causative agent for migraine, particularly migraine with aura.